MACD was designed as a directional indicator and it is implemented as an oscillation to improve its readability and reduce the lag that smoothed indicators suffer.

When trying to understand the state of an indicator sometimes it is often helpful to look at that indicator across a distributions of how it has generated results over a previous period of calculations.

When you asked about the percentage of change of an indicator it implied you are looking for something that might be unusual to see if a percentage change might have any predictive value, or unusual in terms of how it compared to other instruments. Discovering of unusual is often a useful and it is a process used in the Bollinger System as a trigger to send an order to get in, and or out.

When looking at results I find it helpful to understand if the current results are an aberration or just more of the usual results of an indicator. Unusual in a distribution is often viewed through the number of standard deviations a value is from the distribution's modal or central tendency. Trading Blox version 4.x provides a new Z-Score function that can be seen as a indicator in the image below with the bands that a 2-sigma from its central tendency.

Give your thoughts a little more time to think about what you are hoping to achieve and consider if the built-in Z-Score might be a useful tool.

NOTE: 23-Oct-2013
Z-Score Plot is a distribution display of the Average True Range Values. It could just as easily be the MACD values, or the MACD rate of movement values.